DataGridSettings aren't loaded if grid is empty

Radzen.Blazor Components
1

I have a DataGrid with bound LoadData event. I want to Save/Load DataGridSettings on a button click. It works fine except the case when loading settings in a grid with applied filter that shows no data. Please see modified Blazor DataGrid save/load settings with LoadData example and screen recording for details.

@using Radzen
@using RadzenBlazorDemos.Data
@using RadzenBlazorDemos.Models.Northwind
@using Microsoft.EntityFrameworkCore
@using RadzenBlazorDemos.Services
@using Microsoft.JSInterop
@using System.Text.Json
@using System.Linq.Dynamic.Core

@inject IJSRuntime JSRuntime
@inject NavigationManager NavigationManager

@inherits DbContextPage

<p>This example shows how to save/load DataGrid state using Settings property when binding using LoadData event.</p>
<p>The state includes current page index, page size, groups and columns filter, sort, order, width and visibility.</p>
<RadzenButton Click="@(args => Settings = null)" Text="Clear saved settings" Style="margin-bottom: 16px" />
<RadzenButton Click="SaveStateAsync" Text="Save settings" Style="margin-bottom: 16px" />
<RadzenButton Click="LoadStateAsync" Text="Load saved settings" Style="margin-bottom: 16px" />
<RadzenButton Click="@(args => NavigationManager.NavigateTo("/datagrid-save-settings", true))" Text="Reload" Style="margin-bottom: 16px" />
<RadzenDataGrid @ref=grid @bind-Settings="@Settings" AllowFiltering="true" AllowColumnPicking="true" AllowGrouping="true" AllowPaging="true" PageSize="4"
                AllowSorting="true" AllowMultiColumnSorting="true" ShowMultiColumnSortingIndex="true" 
                AllowColumnResize="true" AllowColumnReorder="true" ColumnWidth="200px"
                FilterPopupRenderMode="PopupRenderMode.OnDemand" FilterCaseSensitivity="FilterCaseSensitivity.CaseInsensitive" 
                Data="@employees" IsLoading=@isLoading Count="@count" LoadData=@LoadData TItem="Employee">
    <Columns>
        <RadzenDataGridColumn TItem="Employee" Property="Photo" Title="Employee" Sortable="false" Filterable="false">
            <Template Context="data">
                <RadzenImage Path="@data.Photo" style="width: 40px; height: 40px; border-radius: 8px; margin-right: 8px;" />
                @data.FirstName @data.LastName
            </Template>
        </RadzenDataGridColumn>
        <RadzenDataGridColumn TItem="Employee" Property="Title" Title="Title" />
        <RadzenDataGridColumn TItem="Employee" Property="EmployeeID" Title="Employee ID" />
        <RadzenDataGridColumn TItem="Employee" Property="HireDate" Title="Hire Date" FormatString="{0:d}" />
        <RadzenDataGridColumn TItem="Employee" Property="City" Title="City" />
        <RadzenDataGridColumn TItem="Employee" Property="Country" Title="Country" />
    </Columns>
</RadzenDataGrid>

<EventConsole @ref=@console />

@code {
    RadzenDataGrid<Employee> grid;
    IEnumerable<Employee> employees;
    EventConsole console;

    int count;
    bool isLoading = false;
    async Task LoadData(LoadDataArgs args)
    {
        isLoading = true;

        await Task.Yield();

        var query = dbContext.Employees.AsQueryable();

        if (!string.IsNullOrEmpty(args.Filter))
        {
            query = query.Where(args.Filter);
        }

        if (!string.IsNullOrEmpty(args.OrderBy))
        {
            query = query.OrderBy(args.OrderBy);
        }

        count = query.Count();

        employees = await Task.FromResult(query.Skip(args.Skip.Value).Take(args.Top.Value).ToList());

        isLoading = false;
    }

    public DataGridSettings Settings { get; set; }

    private async Task LoadStateAsync()
    {
        var result = await JSRuntime.InvokeAsync<string>("window.localStorage.getItem", "SettingsLoadData");
        if (!string.IsNullOrEmpty(result))
        {
            Settings = JsonSerializer.Deserialize<DataGridSettings>(result);
        }
    }

    private async Task SaveStateAsync()
    {
        await JSRuntime.InvokeVoidAsync("eval", $@"window.localStorage.setItem('SettingsLoadData', '{JsonSerializer.Serialize<DataGridSettings>(Settings)}')");
    }
}

Load Saved Settings Problem

2

According to the gif you've not pressed Save settings button after filtering by Title.

3

I don't want to save settings after filtering by Title. My gif demonstrates the following scenario:

  1. Apply a filter that produces some result rows
  2. Save the applied filter in settings
  3. Clear the filter
  4. Load the settings saved in step 2 to show that it works as expected and produces the same result as in step 1
  5. Apply a filter that produces no result rows
  6. Load the settings saved in step 2. Expected result: the same as in step 4. Actual result: no rows are shown.
4

You can attach the source code of Radzen.Blazor to your project to debug your case.

5

Debugging the source code showed that the problem is caused by this check. If I delete it, it works as expected.
image

6

Try to change the code to skip <= View.Count() and let me know if it works.

7

The suggested change makes it work when the page number saved in settings is 1. When I save settings with page number > 1, I get the same empty result as in my demonstration. However, in my real application, I don't need to save the page number in settings, so the provided solution is acceptable.

8

Feel free to submit pull request with better solution that will handle all cases.

9

I don't need to handle all the cases right now. Should I make a pull request with the current change suggested by you?

10

I already submitted this change.

11

Ok, thank you very much!